1. Field of the Invention
This invention relates to vascular occlusion removal or thrombus dissolution or destruction devices. More specifically, this invention relates to fluid driven thrombus dissolution catheter systems or catheters. Yet more specifically, this invention relates to apparatuses or thrombectomy catheters for removing vascular obstructions by the creation of a dissolution turbulence or vortex near or adjacent to such obstruction. Catheters of this invention are designed for insertion in body vessels for removing occlusions or obstructions such as thrombus, clot, plaque, emboli, and other vascular or arterial deposits. A particularly important application of the present invention is the dissolution and removal of freshly or recently deposited thrombi and other newly-formed varieties of obstruction referred to above. Concurrently or subsequently, suction or aspiration removal of the resulting occlusion disintegration products is described. Removal of such products provides the decided advantage of reducing possible adverse impact upon downstream or distal organs of occlusion debris. The likelihood of occurrence of macroembolization, distal embolization, and distal infarction are thereby significantly reduced.
2. Description of the Prior Art
The removal of harmful blockages from vessels, ducts, arteries or other passages within the body (sometimes collectively referred to here as "vessels") is typically accomplished by one of several techniques. One technique, balloon angioplasty, involves deployment of a balloon catheter within the obstructed vessel so that, when the balloon is inflated, the constriction or obstruction material is compressed against the vessel walls.
U.S. Pat. No. 4,950,238 issued to Dennis E. Sullivan describes a hydro-rotary vascular catheter which is a variation on the balloon angioplasty. Sullivan discloses a catheter having a rotatable, fluid-directing head. The head of the Sullivan device directs fluid distally, i.e., downstream from the catheter. The Sullivan device further includes an isolation means, e.g., balloons, which are positioned upstream and downstream of the obstruction. After being positioned, the upstream and downstream balloons are inflated with the patient's blood and a pressurized flushing fluid, respectively, to seal off the obstruction. Flushing fluid is ejected distally from the rotary fluid-directing head of the Sullivan catheter which causes the head to rotate. This rotation creates turbulence which, in conjunction with the fluid streams themselves, is disclosed to break down the vessel obstruction. A return channel permits debris to be removed from the constricted area.
The Sullivan device is structurally complicated and has the admitted drawback of occasionally requiring the use of digestive enzymes or other solvents such as those used in some forms of vascular treatment discussed above. Sullivan also requires a shield over the radially oriented fluid-directing orifice to prevent vessel damage due to direct impingement of fluid exiting from the catheter. Further, the Sullivan device is not capable of being precisely placed within the vasculature because it has no structure which would permit it to track a, e.g., steerable guidewire. A problem with both of the above techniques is that they may cause blood vessel wall damage by stretching of the tunica intima and tunica media layers.
A more recent technique, laser angioplasty, uses laser energy to vaporize an obstruction. A typical example of a laser angioplasty catheter is described in U.S. Pat. No. 4,685,458 to Leckrone. As is disclosed in the Leckrone '458 patent, the catheter, which is mounted for rotation and translation about a filament, has a pair of abutments disposed on its distal end. Also included on the distal end of the catheter is a bladder which, when inflated, causes the abutments to bear against the inner surface of the blood vessel so that the space between the abutments defines a working chamber for delimiting the area around an obstruction. A fiber optic connected to a source of laser energy which extends through the catheter, with the distal end of the fiber optic being disposed in one of the abutments. In addition, a suction port is provided between the abutments for removing disintegrated material from the delimited area. Severing means such as a blade or a heated element also may be included for severing and releasing material which is not vaporized by the laser. As with balloon angioplasty, laser angioplasty can result in damage to the blood vessel itself.
Another technique for removal of blockages utilizes what is generally referred to as an atherectomy device or atherectomy catheter. An example of this type of device is disclosed in U.S. Pat. No. 4,631,052 to Kensey. The device of the Kensey '052 patent comprises a bladed cutting head which is rotated by a turbine drive to cut away occlusions in a body vessel. The catheter disclosed in the Kensey '052 patent permits the possibility of vessel wall damage if its rotary head were to be deflected by an especially hard portion of an occlusion.
U.S. Pat. No. 4,747,821 to Kenneth Kensey, et al. discloses a catheter with a high speed moving working head. At several places in the '821 patent the potentially harmful impact of particles generated from a vascular occlusion upon down stream organ structures is recognized. The Kensey, et al. '821 patent deals with the problem by providing a mechanically driven catheter utilizing a pair of non-sharp, impacting surfaces. The impacting surfaces allegedly emulsify the obstruction by repeatedly recycling the dissolution products against the non-sharp impacting surface by means of a distally-emitting vortex flow. No aspiration or removal of dissolution products is disclosed or suggested because removal of the emulsified dissolution products is disclosed to be unnecessary.
U.S. Pat. No. 4,749,376 to Kenneth Kensey et al. discloses a "Reciprocating, Working Head Catheter". The catheter of the Kensey et al. '376 patent comprises an elongated drive wire extending through the catheter body and a motion translator located at the distal end of the catheter. The drive wire is rotated at high speed and the translator translates the rotary motion into reciprocating motion. In this manner the working head is rotated and reciprocated. This motion, in conjunction with a fluid, permits the catheter to open the body vessel in which it is inserted. No aspiration or removal of debris is disclosed or suggested in the Kensey et al '376 patent.
U.S. Pat. No. 4,445,509 to David C. Auth discloses a rotating head cutting tool recanalization catheter having spirally shaped cutting flutes with hardness-differential cutting properties. Plaque and other obstructions are alleged to be removed from organic structures without damage to normal tissue. The cutting apparatus of the Auth et al. patent is disclosed to be rapidly rotated within the blood vessel of a patient by means of an external torque-generating device, e.g., an electric motor. In operation, then, the cutting tool is advanced against a blood vessel lesion or obstruction and the obstruction is differentially cut. The apparatus of Auth et al. has a fluid port in communication with an external suction device so that blood and debris from the cutting operation can be removed from the cutting site.
U.S. Pat. No. 4,631,052 to Kenneth R. Kensey discloses a rotating head or recanalization catheter which is advanced through the body passageways to the site of a restriction. The apparatus of the Kensey '052 patent is disclosed to operate by cutting or by mechanically beating or otherwise agitating or disturbing the blockage material to form an opening. A perfusion structure is provided which provides oxygenated fluids, drugs, contrast media or dyes into the occluded or blocked passage way. U.S. Pat. No. 4,795,438 also to Kenneth Kensey discloses a method and apparatus for forming a restriction in a vessel, such as a fallopian tube. No removal of unwanted vascular obstructions is disclosed or contemplated in the Kensey '438 patent.
U.S. Pat. No. 4,784,636 to Mark A. Rydell discloses a balloon atherectomy catheter. The Rydell '636 patent apparatus has an angular cutting tip fixed to the distal end of an elongated drive tube. A separate rotational drive mechanism is coupled to the drive tube to rotate the drive tip. Provision is made for introducing fluid through the loop of the guide catheter for inflating the balloon and for aspirating blood and loose particles away from the occlusion site. The balloon mechanism is used primarily to retain the distal end of the catheter assembly in place near the occlusion to permit the cutting operation to be performed.
U.S. Pat. No. 5,135,484 to John T. M. Wright discloses a method of removing plaque from vessels in which a partially isolated portion of a vessel (containing an occlusion) is exposed to a slurry. The slurry abrades the plaque and is subsequently withdrawn from the isolated vessel segment.
U.S. Pat. No. 4,715,538 to Horst Lingnau and U.S. Pat. No. 3,120,326 to Ernie D. Willhoite disclose jet nozzles and rotary spray devices, respectively. The inventions of Lingnau and Willhoite are useful for cleaning narrow tubular parts, such as pipes, or for drilling though soft materials by means of Jet or spray nozzles. These references make no mention of possible medical applications of these inventions.
Commonly assigned, published Patent Cooperation Treaty Application PCT/US05220 describes a hydro-rotary thrombectomy catheter which employs a catheter head which is affirmatively rotated, e.g., by means of a cable. The catheter of the '05220 application, therefor, has separate structures to rotate the catheter head, deliver fluid and retrieve fluid and debris from the occlusion site.
Applicants are aware of descriptions of a catheter which comprises a distal end header in fluid communication with a plurality of proximal end- or backward-directed high pressure Jets. The method of operation of such a device is described in an Abstract appearing at Volume 42 of ANGIOGRAPHY, "A Rheolytic System for Percutaneous Coronary and Peripheral Plaque Removal" p. 90 February, 1991. No description of the device is contained in that Abstract. A description of what is thought to be that device appears at 182 RADIOLOGY January, 1992 pp. 263-267 and in the NEW YORK TIMES, Sunday Mar. 21, 1993, section 3. That device is apparently being developed by Possis Medical, and has been offered under the trade designation "AngioJet". Fluids such as saline under high pressure are fed to the distal end of the catheter through the catheter body by means of an off-center input pipe or lumen. The high pressure fluids then are used to break up the occlusion. No rotation of any part of the device is suggested.
None of the above disclosures alone or in combination disclose or suggest the invention of the present application. This invention overcomes the disadvantageous of prior art devices by providing a catheter which can generate a uniquely placeable and controllable, atraumatic, zone of dissolution. The present catheter is reliable, having a relatively uncomplicated structure. The catheter by itself or in conjunction with other devices is widely applicable to the removal of obstructions in both peripheral and coronary applications.